Well I think longer is always better until it just gets too long to where it's unhandy. The bushmaster also has some recoil so I don't think it hurts to have a little weight out on the nose either.
I'd go 20" for all the reasons already mentioned plus it gets all that noise a few inches farther from your ears! Try to find a linear comp. I have owned both 16" and 20", couldn't get rid of the 16" fast enough. Both guns were easily sub MOA. The 20" was just way more comfortable to shoot!
I have one of the first 450BM from the old Bushmaster Company.
It has a 16in barrel and it is called the thumper for a reason.
It has been a great deer rifle.
we have a couple 20"s in the hunting group that have taken multiple deer, as well as an 18" that will be blooded this fall after i loaned my 20" out to my cousin to hunt on the big field with and he one shotted a nice big doe at 160 yds. that one shot sold him and his wife and kids got him one for christmas. he's been a shotgunner for years now and is a full on convert.
a buddy of mine also hunts with an 18" up in the thumb. he whacked a doe at 200 last year with his.
not that a 16" wont get the job done.. but if you're gonna reach out past 100 yds at all.. those extra few FPS will make a difference.
It sounds like the longer barrel would be the better choice for hunting. As far asthe 450 vs 458, I'm not concerned about the restricted area. I hunt up in wexford county which is in the unrestricted area and I have a ruger American in 350 legend that I use if I hunt the southern part of the state. Thanks for the info.
I built an 18in 450BM for a customer and was pleased with the accuracy. We got it to clover leaf at 100 yds with Hornady factory ammo. It sure packs a wallop...